## Key Responsibilities - Develop and audit Solidity smart contracts for lottery mechanics - Implement secure random number generation for winner selection - Build gas-optimized functions for ticket purchasing and prize distribution - Create admin functions for lottery operators (draw, refund, commission withdrawal) - Integrate OpenZeppelin security standards and access controls - Deploy and verify contracts on Polygon network - Collaborate with frontend team on Web3 integration
## Smart Contract Features You'll Build - **Ticket Management**: Purchase validation, quantity limits, price calculations - **Random Winner Selection**: Secure randomness using block hash and timestamp - **Prize Distribution**: Automated winnings calculation and withdrawal system - **Commission System**: Operator fee collection and withdrawal mechanisms - **Refund Logic**: Automatic refunds for expired draws - **Access Control**: Role-based permissions for operators and users - **Event Logging**: Comprehensive event emission for frontend integration
## Required Experience - **4+ years** Solidity development experience - **3+ years** smart contract deployment on mainnet - **Expert knowledge** of Ethereum/Polygon networks and gas optimization - **Production experience** with OpenZeppelin contracts and security patterns - **Strong understanding** of DeFi protocols and tokenomics - Experience with Thirdweb or similar Web3 development frameworks - Knowledge of smart contract testing and auditing practices
## Technical Requirements - Write secure, gas-efficient Solidity code following best practices - Implement proper access controls and security modifiers - Handle edge cases and error conditions gracefully - Optimize contract size and gas consumption - Write comprehensive unit and integration tests - Document contract functions and deployment procedures - Conduct security reviews and vulnerability assessments
Automated HubSpot Invoice System Category: API Integration, CRM, Data Integration, Email Marketing, HTML, MySQL, PHP, Software Architecture Budget: $250 - $750 AUD
02 Apr 2026 03:53 GMT
Teen Respect Article with Stories Category: Article Writing, Book Writing, Content Writing, Copywriting, Editing, Fiction, Ghostwriting Budget: ₹750 - ₹1250 INR
02 Apr 2026 03:52 GMT
NDIS Business Brand Identity Design Category: Arts & Crafts, Branding, Creative Design, Graphic Design, Illustration, Logo Design Budget: $30 - $250 AUD
02 Apr 2026 03:49 GMT
Engaging Educational Cartoon for Grade 1 Category: 2D Animation, AI Animation, AI Content Creation, Animation, Caricature & Cartoons, Fiction, Screenwriting, Script Writing, Video Production, Voice Over Budget: $30 - $250 USD
02 Apr 2026 03:49 GMT
Modern Sleek Used Car Sales Website Category: CSS, Graphic Design, HTML, PHP, User Experience Research, Web Design, Web Development Budget: $250 - $750 USD
Residential Site & Permit Plans Category: 2D Drafting, Architectural Engineering, AutoCAD, Building Architecture, Building Design, Construction Management, PHP, Web Design Budget: $30 - $250 USD
02 Apr 2026 03:45 GMT
Bots making project Category: Android, API, Automation, Bot Development, IPhone, Mobile App Development, PHP, Web Development Budget: ₹37500 - ₹75000 INR
02 Apr 2026 03:43 GMT
Recover Lost Mobile App Access Category: Database Management, Database Programming, Flutter, IOS Development, IPad, IPhone, Mobile App Development, MongoDB Budget: ₹601 - ₹1000 INR
